American drone strikes in southern Yemen have killed nine al Qaeda-linked militants, including the media chief for the group’s Yemeni branch and the son of a prominent U.S.-born cleric slain in a similar attack last month, government officials and tribal elders said Saturday.

In the capital, meanwhile, forces loyal to embattled President Ali Abdullah Saleh opened fire on protesters, killing at least nine and wounding scores, according to medical officials and witnesses. In a northern district of Sanaa, fighting between Saleh’s forces and anti-regime tribesmen and renegade troops killed four supporters of a tribal leader and two civilians. At least 13 people also were wounded, including six civilians.

The airstrikes late Friday in the southeastern province of Shabwa pointed to Washington’s growing use of drones to target al Qaeda militants in Yemen. The missile attacks appear to be part of a determined effort to stamp out the threat from the group, known as al Qaeda in the Arabian Peninsula, which U.S. officials have said is the terror network’s most active and most dangerous branch.